<! DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>while实现1到100相加求和</title>
</head>
<body>
<script>
    var a=1;
    var sum=0;
    while(a<=100){
        sum+=a;
        a++;
    }
    alert("1-100的数相加的和是"+sum)
</script>
</body>
</html>